iH8sn0w has released an updated version of iREB v4.0.x/4.1. The RC2 version of iREB v4.0.x/4.1 now can fix 1015 & 16xx (1600, 1601, 1602, 1603, 1604) errors on all versions of iPhone, iPod Touch, iPad and even Apple TV 2G. The RC1 build of iREB v4.0.x/4.1 could only fix 1015/16xx errors on iPhone 3G/2G & iPod Touch 2G (MB)/1G.

iDevices Supported by iREB v4.0.x/4.1:

For those who don't know, iREB puts your iDevice in a temporary jailbroken state so that you can restore the custom IPSW cooked by PwnageTool or Sn0wbreeze without any restore errors. Usage of iREB v4.0.x/4.1 is extremely simple, just put your device in DFU mode, launch iREB 4.0.x-4.1-RC2.exe, select your device and leave the rest on iREB. When you get white or red screen on your device, start iTunes and restore the custom IPSW using (Shift+Restore) on Windows or (ALT+Restore) on Mac OS X.

The step-by-step procedure to use iREB v4.0.x/4.1 RC2 is exactly similar to iREB v4.0.x/4.1 RC1 which you can find here. Before you can use iREB, make sure you have latest version of iTunes with active internet connection. [via iH8sn0w]

Error 1015 is because your having an iPad BB installed already on your device & your using the stock Apple IPSW for the restore. You need to use a custom IPSW instead if you want to restore successfully w/o any errors. Read this http://bit.ly/mbFORU.